First of all take stuff you read at Phoronix with a grain of salt.
We have had a discussion about this Gallium D3D10/D3D11 project on the Wine irc channels (and there is a summary at wine-devel). The short answer is that Direct3D is very tied to the Windows API and that you just can't easily replace the d3d dlls and forward those to lets say gallium. It would require deep integration with the Wine X11 driver.
Remember we also have initial D3D10 support in Wine, but it is not at a state at which it can run games. Though it is much further along than the Gallium3d project, but it might still take a while before it is usable. If you want to see it finished soon, patches are welcome ;)